Large factory areas are often open to the ambient environment and/or contain large machinery and equipment such as furnaces that produce localized high heat outputs. In these adverse factory conditions, heating or cooling for worker comfort is generally effected by delivering a source of air at a predetermined temperature through a series of main ducts generally positioned overhead so as to be out of the way of factory workers. Drops are provided in fluid communication with the main ducts at spaced locations about the factory typically corresponding to the work stations of the individual workers.
The work stations are generally located adjacent to industrial machinery under the control of the individual. Some machinery produces greater heat than others and, accordingly, the localized ambient temperature at any work station may vary significantly from another. Further, some individuals are more active at their work stations and, therefore, are inclined to feel warmer than those who are not. Of course, some individuals may dress more warmly than others. When these factors are all considered in combination with the fact that individual preferences vary, it should be appreciated that each individual at a work station needs to have the ability to adjust both the volume and direction of air flow being delivered through the main duct and drop to the individual's work station.
This need for customized control has long been recognized in the art. One earlier attempt to provide an adjustable air distribution apparatus to meet this need is disclosed in U.S. Pat. No. 3,919,929 to Harman. The air distribution apparatus disclosed in Harman includes an upper or inlet duct for connection to the drop, a lower or outlet duct for delivering air to work station and a ball joint swivel for interconnecting the inlet and outlet ducts. While effective in providing some control to allow an individual at a work station to adjust and control the conditioned air flow from the air handling system, the Harman apparatus is not without disadvantages.
More specifically, while providing some directional control, the Harman device still fails to provide the actual directional control desired by most individuals. Firstly, directional control is limited by the use of the ball joint swivel. Specifically, engagement of the outlet duct with the upper and outer interfitting spherical portion of the ball joint swivel connection serves to effectively limit the angle of adjustment to only approximately 22.degree. in any direction from the center line axis of the flow path through the inlet duct.
Secondly, a factory environment around industrial machinery is generally oily, greasy and dirty. Accordingly, dust, oil and other debris tends to collect on the exposed surfaces of the swivel connection. When certain subsequent adjustments are made this oil, grease and dirt is actually directed under force into the ball joint connection, initially impairing and in a short time finally completely freezing its movement and operation. Thus, all directional adjustability is quickly lost.
Thirdly, directional control is limited by the controls themselves. Specifically, a damper allows individual control of the flow volume and a separate flow control valve allows individual adjustment of that volume between axial delivery and radial delivery from the exhaust duct. It should therefore be appreciated that true directional control to allow an individual to, for example, deliver air around a tight corner to a specific point is not provided.
While on initial review this deficiency in directional control may not appear to be an important issue, further evaluation proves otherwise. Specifically, it must be appreciated that many plants operate several shifts and, accordingly, more than one individual will be employed at each work station at different times. As pointed out above, different individuals have different preferences regarding air flow and, accordingly, any limits to adjustability that prevent an individual from working comfortably lead directly to lower productivity and employee complaints.
Further, it should be appreciated that manufacturing equipment in factories is often updated and/or modified and/or replaced in order to maintain a competitive edge. The new machinery typically has different dimensions and, accordingly, the position of the work station is often shifted at least to a slight degree relative to the stationary main duct and drop. It is a very expensive process to move the main duct and drop to accommodate the repositioning of the work station. If, however, greater adjustability could be provided for the directional control of the air from the drop, it may be possible to accommodate the repositioning of the work station through a simple adjustment of the air distribution outlet device. Accordingly, the significant additional expense of moving the main duct and drop may be avoided.